At the heart of the problem of educational failure is the low academic quality of the people who become teachers and principals. This low academic quality has been documented by empirical research so many times, over so many years, that it is incredible how this crucial fact gets overlooked again and again in discussions of the problems of our schools.
So long as teacher training courses in education schools are Mickey Mouse, they are going to repel many intelligent people who would like to teach, and we are going to be left with the dregs of the college students. When the resulting pool of "certified" teachers consists disproportionately of these dregs, do not expect them to be even intellectually oriented, much less intellectually competent.
It is impossible to understand what is happening in our schools without understanding the kind of people who run them. But, once you see the poor academic quality of those people, you can easily understand why textbooks have been dumbed down and why there is such bitter opposition by educators to letting exceptionally bright children be taught in separate classes with more advanced material. Do not expect intellectual losers to look favorably on intellectual winners.
Such teachers are the natural prey of education gurus pushing non-intellectual fads with glittering names. If you got rid of every single counterproductive fad in our schools today, but left the same people in place, this would lead only to a new infusion of different counterproductive fads tomorrow.
And there would still be the same bitter opposition to "teaching to the test," which spoils their self-indulgences.